Solvent effects on UV–Vis and FT-IR spectra of indapamide combined with DFT calculations

The present study aimed to analyze the solute–solvent interactions of indapamide using FT-IR, UV–Vis spectroscopies in combination with DFT calculations in four different solvents. The FT-IR spectra of indapamide and solutions of indapamide prepared in ethanol, in methanol, in THF and in DMSO were recorded. The theoretical analysis of probable stable conformers of indapamide was carried out using DFT/B3LYP functional with 6-31G (d,p), 6-311 G ++ (d,p) and plus D3 empirical dispersion function with 6-311 ++G(d,p) basis sets in different media. The optimized geometry and vibrational wavenumbers of indapamide were calculated using DFT method at the same level. Solvent effects of indapamide were performed with conductor-like polarizable continuum model (CPCM) method. The electronic absorption spectra of the molecule were estimated by the time-dependent DFT method at the same level. Solute–solvent interactions are investigated by means of the multi-component linear regression analysis of Kamlet–Taft parameters. Also in this study, the solvent-accessible surface area (SASA) and HOMO–LUMO energy gap were calculated using the quantum chemical calculations.